Tilting mechanism especially for chairs



July'2o,1937. WFHEROLD 2,087,253

` TILTING MEGHANISM ESPECIALLY FOR' CHAIRS July 20, 1937. w. F. HERQLD TILIMNG MECHANISM ESPECIALLY Foa CHAIRS Filed May 16, 1935 3 Sheets-Sheet 2 m. m RPL mun WF.. mm T wm whereby the angularity of movementof the joint Patented July 20, 1937 UNITED STATES PATENT OFFICE TILTING MECHANISM'ESPECIALLY FOR CHAIRS Walter F. Herold, Bridgeport, Conn., assignor to The Bassick Company, BridgeporhConn., a corporation of Connecticut `Application May 16, 1935, Serial )10.21.738 10 Claims. .(Cl. 155.-77)

The present invention relates to tilting mecha; nism especially for chairs, either of the type'in whichl the chair seat is tiltable relatively to a supporting base, or in which the chair back is` tiltable relatively to the chair seat, and is an improvement over the chair iron disclosed in my U. S. vPatent No.2,008,209, dated July 16, 1935, and in which the tilting action takes place in a hinge joint of rubber or other suitable material, the rubber being in the form of a cylinder disposed under permanent pressure and tension between inner and outer co-axial concentric members to which the rubber is in eiect bonded, the relative movement between these members being supported by the torsional strain set up in the compressed rubber.

According t0 the invention disclosed in said application the rubber is under a` predetermined initial tension yieldingly holding the tiltable member in its normal non-tilted position, and as the tiltable member is tilted the tension and resistance in the rubber is built up to support the increased load as the pressure moment is increased during tilting.

vide means whereby the angularity of movement of the joint elements will be of a different order from the angularity of movement of the tilting member with a consequent diierence in the tension set up in the rubber, one embodiment consisting in providing a gradual increase in the angularity of movement of the joint elements and Ianother embodiment in providing a gradual decrease, to the end that the proper angularity of movement to produce the desired tension in the rubber may be produced independently of the particular angularity of movement of the tilting member. It is further proposed to provide means elements will vary at different degrees of tilt of the tilting member, having a diierent movement for a given number of degrees of tilt of the tilting member at one end of the tilting range than at the other end of the tilting range.

With the above and other objects in view embodiments oi my invention are shown in the accompanying drawings and these embodiments will be hereinafter more fully described with reference thereto, and the invention will be finally pointed out in the claims.

In the drawings: v

Fig. 1 is a side elevation of a chair iron embodying the invention, the forward ends of the seat supporting spider arms being broken away.

It is proposed in the present invention to pro` Fig.2 is a vertical sectional view, and showing the tilted position.

Fig. 3 is a bottom plan -horizontal sectional view, taken along lthe line 3-3 of Fig. 1.

Fig. 4 is a horizontal sectional view taken along the line .4-4 of Fig. 1.

Fig. 5 is a side elevation of a modied form o! chair iron, according to the invention, adapted for tiltably supporting a chair back.

Fig.y 6 is a plan view thereof with the seat removed and with certain parts broken away and in section. Y

Figp'l is a side elevation of another modified i form of chair iron, according to the invention.

Fig. 8 is a vertical sectional view showing the same in tilted position.

Fig. 9 is a sideelevation of a further modiiled form of the invention, adapted for tiltably supporting a chair back.

Similar reference characters indicate corresponding parts throughout the several gures of the drawings.

'Referring to the drawings and more paricularly to Figs. 1 to 4 thereof, the chair iron. according to the illustrated exemplary embodiment of the invention shown therein, comprises a pair of angular cross-section spider arms IU--IU adapted to be screwed to the under side of the chair seat in the usual manner, and mounted for tilting movement upon a bracket II having -a vertically disposed socket I2 engaged by a vertically disposed post or spindle I3, the bracket having swivel movement on the post and being retained thereon by a set screw I4 in the bracket engaging an annular groove I5 in the post.

The tiltable mounting of the spider arms is `effected by securing one member of the joint ele ment to the bracket and the other member to the spider arms, the resilient rubber support being disposed between` these members, as will presently more fully appear.

The joint element comprises an outer tubular member I6, an inner tubular member I1, and a cylindrical body of rubber I8 between them, this rubber body being highly compressed and coniined between the members I6 and I1 and being in effect bonded to their surfaces, so that upon relative rotary movement between the members I6 and Il the rubber body is put under torsional strain. In practice the rubber body is bonded to the inner member I1, as by vulcanization, and is then forced into the outer member I6 under great pressure, its diameter prior to insertion in the member I6 being considerably greater than the interior diameter of the member I6, so that the rubber is thus highly compressed and is in effect bonded to the inner surface of the member I6 by the great surface friction set up between them under compression. v

The ends of the inner tubular member I 1 of the joint element project beyond the rubber member I8, as well as beyond the outer tubular member' I 6,

I and are provided with grooves I9 which are adapted to be interlockingly engaged with in- 10 wardly embossed vertically extending ribs 26-20 extending above and below tie-bolt-receiving apertures 2I-2I respectively provided in the sides of the spider arms, a tie-bolt 22, headed at one end and screw threaded at the other being engaged through the bore of the inner tubular joint member I1 and through the apertures 2I2I and having a nut 23 screwed upon its 9 threaded end, this assembly rigidly connecting the spider arms to the member I1 and providing 0 a supporting spacer or strut between the arms. A rib 24 formed on the head of the bolt engages the recess formed by the embossing of the rib 26 and thus locks the bolt against relative turning movement..- I

The bracket I I is provided with a forwardly projecting yoke portion 25 having a transverse connecting bridge portion 26 at its forward end, against which the upper portions of the spider arms I0 rest in the normal non-tilted position of 30 the chair seat. The timng axis of the joint is disposed within the yoke portion forwardly of the vertical swivel axis of the post I3, and the upper surface of the bracket is .inclined rearwardly and downwardly, as at 21, tangentially to the tilting arc of the spider arms, to form a limit stop to the tilting action, as shown in Fig. 2.

The yoke portion of the bracket is provided in each side with cylindrical bearing openings 28-28, in which the end portions of the outer joint member I6 are engaged for rotary movement, as will presently more fully appear.

Within the space between the sides of the yoke portion a tension applying and adjustment lever 29 is disposed, its collar portion 30 being engaged about the intermediate portion of the outer joint member I6 andsecured thereto by a set screw 3I in the collar engaging a recess 32 in the member I6. An adjusting screw 33 having a hand-wheel or nut 34 at its end is engaged in a threaded open- -50.` ing 35 in the end of the lever 29 and is adapted to l bear at its upper endupon a swinging cam member, as will presently more fully appear. It will be obvious that by adjusting the screw 33 the outer joint member I6 is rotated with respect to 55 the bracket Il and the innerjoint member I1,

- and through the torsional strain imposed on the rubber I8 any initial tension may be set u'p in the latter, the greater the initial tension the more force required to tilt the chair seat. The tension 60' it will be observed is increased through the counter-clockwise movement of the lever 29.

Upon the bridge portion 26 there are formed a pair of forwardly projecting ears 36-36 supporting a transverse bearing pin 31 upon which is 65 rotatably engaged the hub portion 38 of a cam member 39, this cam member having a forwardly projecting forked arm 40 engaging a transverse bar 4I secured to and extending between the spider arms Ill-I0, so that as the chair seat and 7b spider arms are tilted swinging movement is imparted to the cam member relatively to the bracket. The cam member has a recessed cam face 42 in which thegend of the screw 33 engages,

y and. the design of the ca m is such that as it is 75'swung it gradually forces the screw 33 and the tension lever 29 downwardly in counter-clockwise direction. In this way the tension build-up in the rubber is gradually increased over that normally produced by the turning of the inner tubular member I1 during tilting, so that in the rearwardly tilted position substantially greater tension is produced in the rubber than would be the case if the outer tubular member I6 of the joint remained stationary. While less effort is requiredto start the tiltingl the build up of pressure will support the increased load as the weight is shifted rearwardly, so that an easy tilting action is produced with adequate support in the tilted position.

'Ihe build up of pressure in the rubber element as the seat is tilted should under normal conditions be such as to compensate for the additional weightvor pressure moment imposed as the tilting is increased, in other words, the increase of tension should be proportionate to the increase of the pressure moment, and therefore approximate stable equilibrium at any point of tilt will result.

In Figs. 5 and 6 I have shown a. modified form in which the invention is embodied in a tilting back for a chair, as for instance a posture chair. A bracket 63 is secured, as by rivets 44, to the rearward ends of the spider arms III-III, and is provided with a pairfof spaced cylindrical bearing portions 45--45 in which the joint element, comprising the outer and inner cylindrical tubular elements I6 and I1 and the intermediate vrubber element I8, is disposed.

A. tilting frame member comprising a rearward chair back supporting portion 46 and side portions'd'I-BT is provided in said side portions with tie-bolt-receiving apertures 48-48 and inwardly embossed locking ribs 49`49 for rigidly connecting the inner member of the joint element, the grooves I9I9 in the ends of the inner member lI1 being engaged with said ribs and the tie-bolt 22 being engaged through said apertures 48-48 and through the bore of the inner member and being secured by the nut 23.

Within the space between the cylindrical beaning portions 45--45 a tension adjustment lever 50 is disposed and projects beneath the swinging cam member, presently to be more fully referred to, the collar portion 5I of the lever being engaged about the intermediate portion of the outer joint member I1 and secured thereto by a setscrew 52. An adjusting screw 53 having a handwheel or nut at its end is engaged in a threaded opening in the end of the lever 56 and is adapted to bear at its upper end upon the under surface of the cam member.

The bracket 53 is provided with a pair of forwardly projecting arms 54-54 supporting a bridge portion 55, against which across bar 56 extending between the side portions 41-41 of the tilting frame member rests in the normal nontilted position. The upper surfaces of the forward ends of the side portions i1-Mare inclined, as at 51, and'engage the under surfaces of the spider arms IIJ- 40 in the fully tilted position to provide a limit stop.

A pair of forwardly projecting ears 58-58 are formed on the bridge portion 55 and support a bearing pin 59 upon which the hub portion 60 of the cam member 6I is rotatably engaged, the cam member being substantially similar in de- .sign and action tothe cam member 39 of the embodiment of the invention shown in Figs. 1

to 4,`being provided with a forwardly projecting fork member 62 engaging a transverse rod 63 secured between the inwardly and forwardly bent endportions 64-64l of the side lportions 41-41 of the ytilting frame'member.

The chair back is mounted for vertical and I angular adjustment relatively to the tilting frame posed recess 65 in which is engaged the vertically disposed rib 66 of a bracket member 61, an elon- 'gated slot 68 beingprovided in the recessed portion 65 and engaged by a bolt 69 extending through an aperture 10 in the bracket member 61, a hand wheel or nut '1I being screwed upon the end of the bolt which normally secures the bracket member 61 in its adjusted `position on' the portion 46, but upon being loosened permits vertical adjustment for the purpose of raising or lowering the height of the chair-back.

A pair of ear lugs 12--12 are provided at the upper end' of the bracket member 61 to which a pair ofear lugs 13-13 'formed on the chair back frame member 14 are pivotally connected by pins 15-15.

Centrally of the frame member 14 and below the lugs 13-13 there are provided a pair of ears 16-16 to which a block member 11 is pivotally connected by means of a pin 18, this block member being provided in its forward face with an inclined T-slot 19 in which is engaged an inclined T-rib 89 provided upon a link-block member 8|, this member 8| having a threaded passage 82 therethrough in which is` engaged a screw shaft 83 journaled in bearing lugs 84-84'formed on the bracket member 61 and provided at its outwardly extended end with a hand wheel 85;

In order to adjust the angular relation of ther ch-air back with respect to the member 61 the screw shaft 83 isturned, in one direction or the Y other whereupon the link block member, 8l is shifted transversely in one direction or the other, and through its `inclined T-rib and slot connec- 'tionlwith the block member 11 swings the lower the cross-bar 63 of the tilting form/,member tol apply gradually increasing tension to the joint element. i

In'Figs. 7 and 8 I have shown another modiiication substantially identical with the embodiment shown in Figs. 1 to 4, but in which a cam member 39a is substituted for the cam member 39, this cam member (i9a being designed to have wise direction from the position shown in Fig. 7

to the position shown in Fig. 8.y

In Fig. 9 I have shown a further modiiication substantially identical with the embodiment shown in Figs. 5 and 6, but in which a cam member Gla, having a gradually decreasing cam face,

similarl to the cam 99, of the embodiment shown in Figs. 7 and 8, is substituted for the cam 6I.

I have illustrated and described preferred and satisfactory embodiments of my invention, but

it will be obvious that changes maybe made therein, Awithin the spirit and scope thereof, as defined in the appended claims.

Having thus described my invention what I claim and desire to secure by Letters Patent is:-

1. In a tilting mechanism, a supporting member and a member tiltable relativelyto saidsupporting member, resilient joint means carried by Y said supporting member comprising -a pair of joint elements and a tension element acting between said joint elements, .means rigidly .connecting one of said joint elements to oneof said members, and means rigidly connectedto said other joint" element and in operative connection with said other member, whereby upon tilting'of `said tiltable member there is relative rotary movement between said joint elements to tension y said tension `element, said operative connection comprising movable movement transmitting means cooperatively connected between saidlast named means and said tiltable member and movable through tilting of said tiltable member adapted to have gradually varying amplitude during equal increments of movement to transmit movement to said last named means as said tiltable member is tilted whereby the rate oftension applied to said tension element during angular movement. of said tiltable member is varied during relative rotation between said joint elements.

2, In atilting mechanism, a supporting member and a member tiltable relatively to said supporting member, resilient joint means carried by said supporting member comprising a pair of joint elements and a tension element acting between said joint elements, means rigidly connecting one of said joint'elements to ksaid tiltable member, and means rigidly connected to said other joint element and in operative connection with said support, whereby upon tilting of said tiltable member there is relative rotary movement between said joint elements'to tension said tension element, said operative connection comprising movable movement transmitting means cooperatively connected between said last named means and said tiltable member and movable through tilting ofsaid tiltable member adapted to have gradually varying amplitude during equal increments of movement' to transmit movement to said last named means as said tiltable member is ftilted whereby the rate of tension-applied to said tension element during angular movement of` said tiltable member is varied during relative rotation between said joint elements.

3. In a tilting mechanism, a supporting member and a member tiltable relatively to said supporting member, resilient joint means carried by said supporting member comprising a pair of joint elements and a tension element acting between said joint elements, means rigidly connecting one of .said joint elements to one of said members, and 'means rigidly connected to said other joint element and in operative connection with said other' member, whereby upon tilting of said tiltablemember there is relative rotary movement between said joint elements to tension said tension element, said operative connection comprising cam means cooperatively connected between said last named means and said tiltable member and movable through tilting of said tiltamplitude during equal increments of movement to transmit movement to said last named means assaid tiltable memberis tilted whereby the rate .l of tension applied to said'tension 'member during equal increments of angular movement of said tiltable member is varied during relative ro` n tationbetween said joint'elements.

4. In a tilting mechanism, a supporting member and a member tiltable relatively to said supporting -member, resilient joint`means carried by said supporting member comprising a pair of joint elements and a tension element' acting between said joint elements, means rigidly connecting one `of said joint elements to one of said members, and means rigidly connected to said other joint element and in operative connection with said other member, wherebyupon tilting of 'said tiltable member-there is relative rotary movement between said joint elements to tension said tension element, said operative connection comprising cam means cooperatively connected between said last named means and said'tiltable member'and movable through tilting of j said tiltable member adaptedto have gradually increasing 'amplitude during equal increments of movement to transmit movement tosaid last named means in a direction to increase the tensionV Iof said tension element as saidv tiltable member is tilted whereby the rate of tension appliedto .said tension member durim 'equal' increments of angular movement of said`tiltable member'is gradually increased during relative rotation between said joint elements. 5. In a tilting mechanism, a supporting memmovement between said joint elements to ten` sion vsaid tension element, said operative connection comprising cam means cooperatively connected between said last named means and saidI tiltable member and movable through tilting of said tiltable member adapted to have gradually decreasing amplitude during equal increments Vof movementfto transmit movement to said last named means in a direction to decrease the tension'of'said tension element as said tiltable member is tilted whereby the rate of tension applied to saidv tension member during equal increments of angular movement of said tiltable member is gradually decreased during relative rotation between said joint elements.v

6. In a tilting mechanism, a supporting member and'a member tiltable relatively to said supporting member, resilient joint lmeans carried byvsaid supporting member comprising a pair of joint elements and a tension element acting between, said joint'elements, means rigidly co-nnecting one vof said joint elements to said tiltable member, and means rigidly connected` to said tension element, s'aid operative connection comprising a cam member pivoted upon said support engaging said last mentioned means and connected to said tiltable member whereby tilting of said tiltable member is adapted 'to impart movement to said cam member and s'aid last named means relatively to said support and whereby the rate of tension applied` to saidv tension member during equal increments of angular movement of said tiltable member is varied by rotation of said other joint element.

7. In a tilting mechanism, a supporting member and a member tiltable relatively to said suD- porting member, resilient joint means carried by said supporting member comprising a pair of joint elements and a .tension element acting between said joint elements, means rigidly connecting one of said joint elements to one of said members, means rigidly connected to said other joint element and in operative connection with said other member, whereby upon tilting of said tiltable member there is relative rotary movement between said joint elements to tension said tension element, said operative connection comf relative rotation between said joint elements, stop direction, one of said joint elements being disposed in a state of initial rotation relatively tothe other joint element to produce initial tension in a direction to normally force said tiltable member in said one direction.

8. In a tilting mechanism, a supporting member and a member tiltable relatively to said supporting member, resilient joint means carried by said supporting member comprising a pair of joint elements and a tension element acting between said joint elements, means rigidly connecting one of said vjoint elements to said tiltable member, and means rigidly connected to said other joint element and in operative connection with Said support whereby `upon tilting of said tiltable member there is relative rotary movement between said joint elements to tension said tension element, said operative connection comprising a cam member pivoted upon said support engaging said last mentioned means and connected to said 1 tiltable member whereby tilting of said tiltable joint elements being disposed in a state of initial rotation relatively to the other joint element to produce initial tension in a direction to normally force said tiltable member in said one direction.

9. In a tilting mechanism, a supporting member and a member tiltable relatively to said supporting member, resilient joint means carried by said supporting member comprising a pair of joint elements and a tension element acting between said joint elements, means rigidly connecting one of said Joint elements to saidtiltable member, and means rigidly connected to said other joint element and inoperative connection with said support, whereby upon tilting of said tiltable member there is relative rotary movement between said joint elements to tension said tension element, said operative connection comprising a cam member pivoted upon said support engaging said last mentioned means and`con-j nected to said tiltable member whereby tilting of said tiltable member is adapted to impart movement to said cam member and said last named means relatively to said support and whereby the rate of tension applied to said tension member during equal increments of angular movement of said tiltable member is varied by rotation of said other joint member, and an adjustment screw carried by said last named means engaging said cam to adjust the relation of said last named means to said cam.

10. In a tilting mechanism, a supporting member and a member tiltable relatively to said supporting member, resilient joint means carried by said supporting member comprising -a ypair of ""Whereby upon tilting ofsaid tiltable member there is relative rotary movement between said joint elements to tension said tension element, said operative connection comprising movable 4movement transmitting means cooperatively connected between said last named means and said tiltable member and movable through tilting of said tiltable member adapted to have gradually varying amplitude during equal increments of movement to transmit movement to said last named mns as said unable member 1s tilted whereby the rate of tension applied to said tension element during angular movement of said between said joint elements.

WALTER F. HEROLD. 

